In 1994, an Arizona jury convicted Christopher J. Spreitz ("Spreitz") of first-degree murder. The victim was thirty-nine year old Ruby Reid ("Reid"). Finding that the cruelty of the murder outweighed any mitigating circumstances, the trial judge sentenced Spreitz to death. Spreitz appeals the district court's denial of his petition for a writ of habeas corpus challenging his conviction and sentence. We affirm the district court's judgment with respect to Spreitz's conviction,1 and reverse with respect to his sentence.2
In challenging his sentence, Spreitz argues that the Arizona Supreme Court unconstitutionally affirmed his death sentence by failing to consider mitigating evidence of his longstanding alcohol and substance abuse. He contends that the state court refused to consider, as a matter of law, this evidence in mitigation because he did not establish a causal connection between the crime and his long-term alcohol and substance abuse. In Eddings v. Oklahoma , 455 U.S. 104, 110, 102 S.Ct. 869, 71 L.Ed.2d 1 (1982), the Supreme Court held that under both the Eighth and Fourteenth Amendments, a sentencer in a capital case may not "refuse to consider, as a matter of law , any relevant mitigating evidence" offered by the defendant. Id. at 114, 102 S.Ct. 869. Although a sentencer "may determine the weight to be given relevant mitigating evidence ... they may not give it no *1265weight by excluding such evidence from their consideration." Id. at 114-15, 102 S.Ct. 869 (footnote omitted). In interpreting and applying Eddings , the Supreme Court has explained that "full consideration of evidence that mitigates against the death penalty is essential if the [sentencer] is to give a reasoned moral response to the defendant's background, character, and crime." Penry v. Lynaugh (Penry I ), 492 U.S. 302, 328, 109 S.Ct. 2934, 106 L.Ed.2d 256 (1989), abrogated on other grounds by Atkins v. Virginia , 536 U.S. 304, 122 S.Ct. 2242, 153 L.Ed.2d 335 (2002) (internal quotation marks and citation omitted). Moreover, the Supreme Court has been clear: requiring a defendant to prove a causal nexus between his mitigating evidence and the crime is "a test we never countenanced and now have unequivocally rejected." Smith v. Texas , 543 U.S. 37, 45, 125 S.Ct. 400, 160 L.Ed.2d 303 (2004) (per curiam).
At the time of Spreitz's sentencing, Arizona Revised Statute Annotated § 13-703(G) (1994)3 listed five mitigating factors, and Arizona case law additionally recognized nonstatutory mitigating factors, including, for example, a defendant's difficult family background or mental condition not severe enough to qualify as a statutory mitigating factor. In an en banc decision of our court, McKinney v. Ryan , 813 F.3d 798 (9th Cir. 2015), cert denied , --- U.S. ----, 137 S.Ct. 39, 196 L.Ed.2d 197 (2016) (mem), we explained:
For a period of a little over 15 years in capital cases, in clear violation of Eddings , the Supreme Court of Arizona articulated and applied a "causal nexus" test for nonstatutory mitigation that forbade as a matter of law giving weight to mitigating evidence, such as family background or mental condition, unless the background or mental condition was causally connected to the crime.
Id. at 802. As a result, we held in McKinney that "[a]pplication of the causal nexus test to nonstatutory mitigating factors violated Eddings , for it resulted in Arizona courts being entirely forbidden, as a matter of state law, to treat as a mitigating factor a family background or a mental condition that was not causally connected to a defendant's crime." Id. Spreitz argues that the Arizona Supreme Court applied its causal nexus test in his case, refusing to consider evidence of his long-term substance and alcohol abuse because he did not adequately establish a causal connection between that history of abuse and his crime.
As in McKinney , "the precise question before us is whether the Arizona Supreme Court applied its unconstitutional causal nexus test in affirming [Spreitz]'s death sentence on de novo review."4 Id. at 804 (emphasis and internal quotation marks omitted). For the reasons that follow, we conclude that it did.
*1266I.
A. Spreitz's Crimes, Conviction, and Sentence
On May 25, 1989, the police arrested Spreitz after discovering Ruby Reid's body in the desert. Upon questioning, Spreitz confessed to murdering Reid. We briefly provide the facts of the murder.
On the evening of May 18, after drinking heavily and being rejected by the woman he was dating, Spreitz "picked up" Reid at a convenience store. State v. Spreitz (Spreitz I ), 190 Ariz. 129, 945 P.2d 1260, 1264-65 (1997).5 In his confession, Spreitz claimed that Reid voluntarily left with him and that his understanding was that they would have sex later that evening. Id. at 1265. Spreitz further claimed that he drove her out to the desert, where Reid decided she no longer wanted to have sex. Id. The two fought as a result. Id. Spreitz explained that Reid slapped him and that he responded by punching her in the mouth. Id. Spreitz then sexually assaulted Reid-"remov[ing] her clothing and ha[ving] vaginal intercourse with her." Id. Spreitz also recounted that he hit Reid in the head multiple times with a rock "to make her stop yelling." Id. He explained that he left Reid without knowing whether she was alive or dead. Id.
Shortly after leaving Reid in the desert, Spreitz was stopped by a Tucson police department officer. Id. at 1264. The officer observed that Spreitz had a ripped shirt, smelled of feces, and appeared to be covered in blood and fecal matter. Id. In addition, when detectives later searched Spreitz's car, they found blood spatter in the trunk, some of which was inconsistent with Spreitz's blood characteristics. Id. at 1265.
On Monday morning, May 22, Reid's naked and decomposing body was discovered on the outskirts of Tucson. Id. At trial, "the medical examiner testified that, due to the advanced state of decomposition, he could not determine the full extent and nature of [Reid]'s injuries." Id. Even so, he was able to observe "bruising on the legs, arms, and back; bruising and abrasions on the buttocks ; several broken ribs; internal bleeding; a broken jaw ; several head lacerations; and a skull fracture where the skull had been 'shoved in.' " Id. The medical examiner concluded that Reid had been killed by "blunt-force trauma to the head." Id.
In addition to finding Reid's body "[a]t the scene, police detectives observed tire tracks leading back to the pavement, oil stains in the dirt, footprints, and drag marks in the dirt leading away from the body. They also found feces-stained pants, tennis shoes, socks, a used tampon, and a torn brassiere. Two blood-stained rocks lay next to the body." Id. A few days later, police arrested Spreitz. Id.
On June 2, 1989, a grand jury indicted Spreitz for first-degree murder, Ariz. Rev. Stat. Ann. §§ 13-1105, 13-703 ; sexual assault, Ariz. Rev. Stat. Ann. §§ 13-406(A) & (B) ; and kidnapping, Ariz. Rev. Stat. Ann. §§ 13-304(A)(3) & (B). Spreitz I , 945 P.2d at 1265. After five years of pre-trial proceedings mostly regarding the admissibility of DNA evidence, a seven-day jury trial began on August 9, 1994. Id. at 1266. After the conclusion of the trial, the jury returned guilty verdicts on all three counts: first-degree murder (both premeditated and felony murder), sexual assault, and kidnapping. Id .
Prior to both his aggravation-mitigation and sentencing hearings before the trial *1267judge, Spreitz submitted evidence and a memorandum in support of certain mitigating circumstances. As noted earlier, at the time of Spreitz's sentencing, Arizona's death penalty statutes provided a list of five specific mitigating factors; Arizona case law recognized nonstatutory mitigating factors as well. See Ariz. Rev. Stat. Ann. § 13-703(G) ; McKinney , 813 F.3d at 802. Spreitz argued as nonstatutory mitigating factors: "(1) his dysfunctional family life and lack of socialization; (2) a history of alcohol and drug abuse; (3) his expressions of remorse; [ (4) ] his good behavior while incarcerated; [ (5) ] his lack of adult convictions; [and (6) ] no prior record of violent tendencies." Spreitz I , 945 P.2d at 1279. Spreitz argued as statutory mitigating factors: (1) his age at the time of the murder, Ariz. Rev. Stat. Ann. § 13-703(G)(5), and (2) that his "capacity to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of law was significantly impaired [due to alcohol use], but not so impaired as to constitute a defense to prosecution," id. § 13-703(G)(1) ; see Spreitz I , 945 P.2d at 1279.
Spreitz provided evidence of and argued for all the foregoing mitigating circumstances but focused heavily on a combination of his relationship with his mother and his long history of alcohol and substance abuse. To that end, Spreitz submitted a written report by and presented testimony from an examining psychologist, Dr. Todd Flynn, Ph.D. After conducting interviews and research, Dr. Flynn concluded that Spreitz's longstanding alcohol and substance abuse should be considered as both a statutory and nonstatutory mitigating factor. In his report, which was admitted into evidence at the aggravation and mitigation hearing, Dr. Flynn repeatedly emphasized Spreitz's longstanding substance abuse6 :
By age twelve or thirteen, Chris Spreitz began drinking alcohol and smoking marijuana. By age 15, he drank steadily on weekends and would have a shot of vodka before school.
The collateral information shows that the alcohol abuse continued to intensify after he left home. A variety of persons ... described him as a heavy drinker. This includes a second cousin, Scott [Jouett], who saw him to be intoxicated, "a majority of the time," when he was visiting Santa Barbara a week before the current offense. To the interviewing investigator, Mr. [Jouett] also described, "several different occasions when Chris has blackouts," while drinking alcohol.
It appears completely clear from the available information that Chris Spreitz had a longstanding problem with alcohol which probably reached the level of physical dependence. He described himself as drinking in the morning as early as age 15. Virtually everyone else who spent much time with him described him as a heavy drinker.
Ultimately, Dr. Flynn concluded that Spreitz's alcohol abuse, childhood home life, and stunted development, combined with rejection by his girlfriend on the day of the crime, and intoxication at the time of the crime, led to the murder.
At the end of his report, Dr. Flynn summarized his findings and opinions with respect to both statutory and nonstatutory mitigating factors. He opined that both Spreitz's age, Ariz. Rev. Stat. Ann. § 13-703(G)(5), and impaired capacity to appreciate the wrongfulness of his conduct or conform his conduct to the law, Ariz. Rev. Stat. Ann. § 13-703(G)(1), were mitigating *1268statutory factors. As to § 13-703(G)(5), specifically, Dr. Flynn opined that a combination of a disturbing upbringing in a "pathogenic, emotionally neglectful home environment," and "[y]ears of alcoholism intoxication" combined to cause major deficits in Spreitz's social and emotional development. As to § 13-703(G)(1), Dr. Flynn offered a similar conclusion. In light of Spreitz's "history of alcoholism ... , a significant but unknown degree of alcohol intoxication is likely" on the night of the crime. In addition, Spreitz's "history strongly suggests years of early experiences likely to have caused a build-up of pent-up angry, aggressive feelings toward women generally (and older women especially) which may have burst forth with uncontrollable intensity with or without alcohol intoxication." Dr. Flynn concluded that Spreitz's intoxication on the night of the crime coupled with his early childhood experiences "likely ... contributed to an uncontrollable outburst of aggression" and inability to control his conduct.
Dr. Flynn also concluded that certain nonstatutory mitigating factors were present. The nonstatutory mitigating factors included, in his opinion: Spreitz's low potential for future violence, the "failure of [Spreitz's] parents to provide treatment for alcohol abuse in [his] teenage years," and the "emotionally deprived, physically punitive home environment" of Spreitz's upbringing. Dr. Flynn also emphasized that even if both statutory mitigating factors failed to satisfy the statutory threshold, they may still "be appropriately considered ... as nonstatutory mitigation."
On November 28, 1994, the trial court conducted an aggravation-mitigation hearing. At the hearing, Spreitz called three mitigation witnesses: Dr. Flynn and two correctional officers from the Pima County jail, where Spreitz was incarcerated. The State did not offer any witnesses or evidence at the hearing. Dr. Flynn testified consistently with his report, as detailed above.
On the same date, a probation officer filed a Pre-Sentence Report, which concluded:
It appears the defendant became involved in the senseless commission of the instant offense due to his alcohol and drug abuse. After five years in custody, he now admits his substance abuse problem; however, this does not condone his involvement in the offense. It is unfortunate the victim died before the defendant had his revelation.
Prior to the sentencing hearing, Spreitz also submitted several letters from friends, family, and jail personnel.
On December 21, 1994, the trial court conducted a sentencing hearing. Spreitz, Spreitz's counsel, the victim's sister, and the prosecutor each addressed the court.7 The prosecutor first disputed the mitigating evidence presented by Spreitz at the mitigation-aggravation hearing. With respect to Spreitz's alcohol abuse, the prosecutor argued that Spreitz's intoxication at the time of the crime did not meet the statutory definition for mitigation under § 13-703(G)(1) because his conduct both during the murder and afterwards demonstrated that "he knew what he was doing." The prosecutor emphasized that the evidence revealed that Reid had been forcibly abducted and stuffed into the trunk of a car, thus forcing her to spend time "contemplat[ing] the uncertainty of her fate." The prosecutor argued that the evidence revealed signs of struggle and that the serious injuries to Reid's body belied any notion that Spreitz did not know what he *1269was doing. The prosecutor further argued that the fact that Reid defecated on herself revealed that she was terrified prior to her murder. In sum, the prosecutor argued that given both the heinous nature of the crime and the manner in which Reid suffered, a finding in aggravation that Reid was murdered in an "especially cruel manner" was warranted.
After a short recess, the sentencing judge rendered oral findings addressing the aggravation and mitigation issues. He then imposed a sentence of death.8 Following the hearing, the sentencing judge filed a judgment setting forth written findings.
The judge first found one aggravating circumstance-that the offense was committed in an "especially cruel manner." Ariz. Rev. Stat. Ann. § 13-703(F)(6). The judge proceeded to review the "many factors [that were] submitted in mitigation," ultimately finding five mitigating circumstances of various levels of significance:
[1] A mitigating circumstance defense submitted was that the defendant had an extremely disruptive childhood .... The court finds the home was sub-normal, not even a minimally healthy one for developing children; and it is obvious the defendant suffered a disruptive middle childhood-had a punitive, controlling, cold mother, who he could not please, no matter what he did.
The defendant in his life turned to substance abuse-alcohol and some suggestion he was using cocaine and other drugs. However, the court does not find such is a mitigating circumstance that impaired his ability to make a judgment on whether he was acting rightfully or wrongfully in the death of the victim.
The defendant's history of intoxication is longstanding. He had been abusing substances for close to ten years of his life at the time of this offense when he was twenty-two. Again, the court does not believe that the substance abuse or intoxication impaired the defendant's ability and capacity to appreciate the wrongfulness of his conduct to any significant degree. ... The court does not believe intoxication is any sort of mitigating circumstance.
...
[2] The court acknowledges that the defendant has begun a process of improvement and emotional growth while confined at the Pima County Jail, where he has taken part in education programs. Correctional officers have testified he was a prisoner who caused no problems.
[3] The age of the defendant at the time of the offense (twenty-two) is not a mitigating circumstance in and of itself. Immaturity probably is, but the court does not believe immaturity was a significant mitigating circumstance.
[4] The court finds that Mr. Spreitz has no criminal history of a felony nature-there is no history or propensity for acts of violence.
[5] The court believes the defendant is capable of being rehabilitated. The court does not know whether he has a good prognosis for the future, but the court believes he can be rehabilitated.
In conclusion, the judge found that "the mitigating circumstances [were] not sufficient to balance the aggravating circumstances, nor [were] they sufficiently substantial to call for leniency." He thus imposed a death sentence as to the first-degree murder conviction.
*1270B. Spreitz's Appeal and Post-Conviction Proceedings
Spreitz appealed his conviction and sentence to the Arizona Supreme Court with the assistance of new counsel. The Arizona Supreme Court affirmed Spreitz's conviction and sentence after conducting its own independent review of the record.9 In reviewing the mitigating evidence, the court found four of the five mitigating circumstances that the sentencing judge had found, declining to find Spreitz's good behavior while in jail awaiting sentencing as a mitigating circumstance. Spreitz I , 945 P.2d at 1280-81. The court explained:
[1] "We agree with the sentencing judge that defendant's upbringing was subnormal." Id. at 1280.
[2] "We also find that the sentencing judge ... properly found that his emotional immaturity was not a significant mitigating factor." Id. at 1281.
[3] "We agree that the record supports the sentencing judge's findings that defendant had no previous adult felony convictions, no prior acts of violence, and
[4] that the defendant is capable of rehabilitation." Id.
The Arizona Supreme Court also added that it considered remorse as an additional nonstatutory mitigating factor. Id.
The court addressed Spreitz's history of alcohol and substance abuse as follows:
The record demonstrates defendant's longtime substance abuse problems. We note, however, that defendant's general problems with substance abuse are not essential to our decision here. We therefore decline to conclude that defendant was impaired by alcohol consumption to an extent that it interfered with his "capacity to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of the law." A[riz]. R[ev]. S[tat]. [Ann.] § 13-703(G)(1) ; see also State v. Medrano , 185 Ariz. 192, 194, 914 P.2d 225, 227 (1996) (citing [ State v. ] Stokley , 182 Ariz. [505,] 520, 898 P.2d [454,] 469 [1995] ).
Id. at 1280-81. In the only other portion of its opinion addressing Spreitz's history of alcohol and substance abuse, the court said:
The sentencing judge found that defendant's ability to appreciate the wrongfulness of his conduct was not impaired on the night of the murder to any significant extent by substance abuse, emotional disorders, situational stress, or by a combination of these. Our review of the record convinces us that the trial court's finding was proper.
Id. at 1281.
The Arizona Supreme Court agreed with the trial court's aggravation finding that the murder was done in an especially cruel manner, id. at 1279, and then proceeded to reweigh the applicable aggravating and mitigating factors, finding that "the aggravating circumstance of especial cruelty in defendant's murder of Ruby Reid outweigh[ed] all factors mitigating in favor of leniency." Id. at 1282. It affirmed his death sentence. Id . at 1283. Spreitz filed a petition for a writ of certiorari, which the United States Supreme Court denied. Spreitz v. Arizona , 523 U.S. 1027, 118 S.Ct. 1315, 140 L.Ed.2d 479 (1998) (mem).
In March 2000, represented again by new counsel, Spreitz filed a petition for post-conviction relief in the Arizona Superior Court ("PCR court"). See Ariz. R. Crim. P. 32.1. Spreitz alleged, inter alia , that the sentencing judge and the Arizona Supreme Court committed error by failing *1271to consider his history of alcohol and substance abuse as a nonstatutory mitigating factor apart from its causal connection to the murder-i.e., Eddings error. He also alleged that his appellate counsel was ineffective for failing to raise the sentencing judge's Eddings error on appeal to the Arizona Supreme Court. Spreitz additionally raised several new claims of trial-counsel-ineffectiveness.
The PCR court denied all of Spreitz's claims and entered an order dismissing his petition for post-conviction relief. In Part 3 of its order, the PCR court discussed Spreitz's claims of "nexus-error"-that both the trial court and the Arizona Supreme Court erred when they failed to consider Spreitz's longstanding alcohol and substance abuse on the basis that Spreitz had failed to establish a causal nexus between the long-term substance abuse and the murder.10 The PCR court dismissed the claim11 as waived, reasoning that Spreitz had failed to raise the issue on direct appeal. Nonetheless, the PCR court addressed the merits of the nexus-error claim in the course of analyzing Spreitz's argument that his appellate counsel was ineffective for failing to raise it. In doing so, the PCR court explained that the claim failed because:
[I]t must be demonstrated, under A[riz]. R[ev]. S[tat]. [Ann.] § 13-703(G)(l), that there is a causal link between the history of alcohol or substance abuse and the offense itself. E.g. , State v. Stokley , [ ] 182 Ariz. [505,] 523, [898 P.2d 454, 472 (Ariz. 1995) ]. Without some basis for explaining or defining the individual's behavior at the time of the offense, the Petitioner's history of alcohol or substance abuse would be inconsequential (which is exactly what the trial court and Supreme Court concluded). State v. Kayer , 194 Ariz. 423, 984 P.2d 81 [31] ( [Ariz.] 1999).
At times, the court can and should consider an individual's long-term alcoholism and substance abuse, usually in conjunction with other factors or diagnosis, as non-statutory mitigation. However, the impact or effect of the alcoholism or substance abuse must be substantial and of such severity that it provides a sufficient basis for explaining the defendant's conduct, character or ability to control his behavior at the time of the offense. [Citations omitted].
As previously discussed, there is no evidence in Petitioner's case to suggest that he suffered any long-term effects from his alcohol or drug abuse that precluded him from controlling his behavior. Petitioner did not suffer from any cognitive or emotional deficits that rendered him incapable of controlling his conduct. Therefore, the trial court did not err in failing to find Petitioner's history of alcohol or substance abuse as a separate, non-statutory mitigating factor. [Citation omitted].
Spreitz filed a petition for review in the Arizona Supreme Court challenging the PCR court's judgment. The Arizona Supreme Court summarily affirmed the PCR court's merits determination with respect to Spreitz's Eddings claims. State v. Spreitz (Spreitz II ), 202 Ariz. 1, 39 P.3d 525, 527 (2002).
Spreitz filed his federal habeas petition in February 2003. He alleged in claim seven *1272that the sentencing judge and the Arizona Supreme Court had both committed nexus-error with respect to his long-time alcohol and substance abuse, and that appellate counsel was ineffective for failing to argue the sentencing judge's nexus-error on direct appeal to the Arizona Supreme Court.
The district court denied all of Spreitz's claims. With respect to the alleged nexus-error by both the sentencing court and the Arizona Supreme Court, the district court found the claims procedurally barred, relying on the PCR court's determination that Spreitz had waived the claims because he could have raised them on direct appeal but failed to do so. The district court concluded that Spreitz had properly exhausted his ineffective assistance of appellate counsel claim, and thus addressed the alleged nexus-error in that context, ultimately concluding it was not meritorious. Accordingly, the district court concluded that "appellate counsel's failure to raise this issue on appeal does not constitute ineffectiveness."
Spreitz timely appealed.
II. Jurisdiction and Standard of Review
We have jurisdiction pursuant to 28 U.S.C. §§ 1291 and 2253(a), and review de novo the district court's denial of a writ of habeas corpus. Poyson v. Ryan , 879 F.3d 875, 887 (9th Cir. 2018). Because Spreitz filed his federal habeas petition after April 24, 1996, he must satisfy the Antiterrorism and Effective Death Penalty Act ("AEDPA"). Under AEDPA, we may not grant habeas relief unless the state's adjudication of Spreitz's claim (1) "was contrary to ... clearly established federal law[ ] as determined by the Supreme Court," (2) "involved an unreasonable application of" such law, or (3) "was based on an unreasonable determination of the facts in light of the evidence presented in the State court proceeding." ( 28 U.S.C. § 2254(d) ). "In making this determination, we look to the last state court decision to address the claim," White v. Ryan , 895 F.3d 641, 665 (9th Cir. 2018) (citing Wilson v. Sellers , --- U.S. ----, 138 S.Ct. 1188, 1192, 200 L.Ed.2d 530 (2018) ), which for Spreitz's nexus-error claim is that of the PCR court.
Spreitz argues that the PCR court's decision was "contrary to" Eddings v. Oklahoma , 455 U.S. 104, 102 S.Ct. 869, 71 L.Ed.2d 1 (1982). "A state court's decision is contrary to clearly established federal law if it 'applies a rule that contradicts the governing law set forth in [U.S. Supreme Court] cases' or arrives at a different result in a case that 'confronts a set of facts that are materially indistinguishable from a decision of [the Supreme] Court.' " Castellanos v. Small , 766 F.3d 1137, 1146 (9th Cir. 2014) (alteration in original) (quoting Williams v. Taylor , 529 U.S. 362, 405-06, 120 S.Ct. 1495, 146 L.Ed.2d 389 (2000) ). "If the state court applies a legal standard that contradicts clearly established [Supreme Court] law, we review de novo the applicant's claims, applying the correct legal standard to determine whether the applicant is entitled to relief." Id. (citation omitted).
III. Discussion
As discussed supra , the precise question we must decide is whether the Arizona Supreme Court applied its unconstitutional causal nexus test in violation of Eddings when it affirmed Spreitz's death sentence. To answer that question, we must first determine whether the claim is properly before us. After concluding that Spreitz's claim could not have been procedurally defaulted, we turn to the level of deference we must accord the PCR court's ruling on Spreitz's Eddings claim under AEDPA. Because the PCR court's decision was contrary *1273to clearly established Supreme Court precedent, we accord that decision no deference and review Spreitz's Eddings claim de novo. We conclude that the Arizona Supreme Court violated Eddings by impermissibly requiring that Spreitz establish a causal connection between his longstanding substance abuse and the murder before considering and weighing the evidence as a nonstatutory mitigating factor. Finally, having determined that the Arizona Supreme Court applied an unconstitutional causal nexus test in its sentencing procedure, we turn to whether the error was harmless under Brecht v. Abrahamson , 507 U.S. 619, 113 S.Ct. 1710, 123 L.Ed.2d 353 (1993). We conclude that the error was not harmless and therefore reverse the district court's judgment with respect to Spreitz's sentence.
A.
Under the doctrine of procedural default, a federal habeas court "will not review the merits of claims, including constitutional claims, that a state court declined to hear because the prisoner failed to abide by a state procedural rule." Martinez v. Ryan , 566 U.S. 1, 9, 132 S.Ct. 1309, 182 L.Ed.2d 272 (2012). "We review de novo a district court's conclusion that a claim is procedurally defaulted." Cooper v. Neven , 641 F.3d 322, 326 (9th Cir. 2011).
Here, the district court concluded that both of Spreitz's Eddings claims-that the sentencing court and the Arizona Supreme Court applied an unconstitutional causal nexus test-were procedurally defaulted, because the PCR court found each claim waived for failure to raise them on direct appeal. This conclusion, however, is erroneous with respect to Spreitz's claim that the Arizona Supreme Court violated Eddings . After all, "[t]he Arizona Supreme Court reviews capital sentences de novo, making its own determination of what constitute[s] legally relevant aggravating and mitigating factors, and then weighing those factors independently. Ariz. Rev. Stat. Ann. § 13-755. The Arizona Supreme Court 'conducts a thorough and independent review of the record and of the aggravating and mitigating evidence to determine whether the sentence is justified.' " McKinney , 813 F.3d at 819 (emphasis removed) (quoting State v. McKinney , 185 Ariz. 567, 917 P.2d 1214, 1225 (1996) ). Spreitz could not have raised on direct appeal his claim that the Arizona Supreme Court violated Eddings in performing its de novo review of Spreitz's death sentence. The first opportunity he had to raise that claim was before the PCR court, at which time he did so. Thus, Spreitz's claim is not procedurally defaulted and is properly before us.12
*1274B.
Because Spreitz's claim that the Arizona Supreme Court applied an unconstitutional causal nexus test to his nonstatutory mitigating evidence of long-time alcohol and substance abuse is properly before us, we next determine the level of deference to accord the PCR court's adjudication of that claim. As discussed above, although the PCR court first declared the claim waived, it proceeded to adjudicate the claim on the merits. In denying the claim, the PCR court explained:
Without some basis for explaining or defining the individual's behavior at the time of the offense, [Spreitz]'s history of alcohol or substance abuse would be inconsequential (which is exactly what the trial court and Supreme Court concluded).
At times, the court can and should consider an individual's long-term alcoholism and substance abuse, usually in conjunction with other factors or diagnosis, as non-statutory mitigation. However, the impact or effect of the alcoholism or substance abuse must be substantial and of such severity that it provides a sufficient basis for explaining the defendant's conduct, character, or ability to control his behavior at the time of the offense.
....
As previously discussed, there is no evidence in [Spreitz]'s case to suggest that he suffered any long-term effects from his alcohol or drug abuse that precluded him, from controlling his behavior. Petitioner did not suffer from any cognitive or emotional deficits that rendered him incapable of controlling his conduct. Therefore, the trial court did not err in failing to find [Spreitz]'s history of alcohol or substance abuse as a separate, non-statutory mitigating factor.
In other words, the PCR court concluded that Spreitz's longstanding alcohol and substance abuse could only be considered a nonstatutory mitigating factor if it "provide[d] a sufficient basis for explaining the defendant's conduct, character, or ability to control his behavior at the time of the offense ." This discussion both accurately described the causal nexus test and approved of it.
Such reasoning is contrary to clearly established federal law. As explained in McKinney , "the causal nexus test clearly violates Eddings ." 813 F.3d at 810. Therefore, "[b]ecause the state court used the wrong standard, we need not defer to that decision." Hardy v. Chappell , 849 F.3d 803, 820 (9th Cir. 2016).
C.
Because the PCR court's decision was "contrary to" clearly established law, we review de novo the merits of Spreitz's Eddings claim. 28 U.S.C. § 2254(d)(1). We therefore consider whether the Arizona Supreme Court applied its unconstitutional causal nexus test in reviewing and affirming Spreitz's death sentence. In so doing, "we look only to the decision of th[e Arizona Supreme Court], ... only [considering] ... the decision of the sentencing judge ... to the degree it was adopted or substantially incorporated by the Arizona Supreme Court." McKinney , 813 F.3d at 819.
1.
Our decision in McKinney frames our consideration of the Arizona Supreme Court's decision and Spreitz's claim. McKinney makes clear that the Arizona Supreme Court consistently articulated and applied its unconstitutional causal nexus test during the period in which Spreitz's *1275death sentence was litigated in the trial court and reviewed by the Arizona Supreme Court. Id. at 824. Moreover, McKinney makes plain that although on habeas review, we generally apply a "presumption that state courts know and follow the law," "the Arizona Supreme Court's consistent articulation and application of its causal nexus test ... make such a course impossible." Id. at 803 (internal quotation marks and citation omitted). In appeals heard from the late 1980s until at least 2002, see State v. Canez , 202 Ariz. 133, 42 P.3d 564, 594 (2002), it was unmistakably clear that "the Arizona Supreme Court did not know and follow federal law." Id. (internal quotation marks omitted).13 Therefore, just as in McKinney and subsequent cases applying McKinney , see, e.g. , Poyson , 879 F.3d at 889, "the presumption" that the Arizona Supreme Court knew and followed the law "is rebutted" here as well. McKinney , 813 F.3d at 804.
That said, McKinney does not dispose of Spreitz's claim. We must still review the Arizona Supreme Court's decision to determine whether it did, in fact, apply its unconstitutional causal nexus test in Spreitz's case. In doing so, we are mindful of the fact that at the time the Arizona Supreme Court decided Spreitz's appeal, "if there is to be a presumption, it is that the Arizona Supreme Court violated the dictates of Lockett and Eddings ." Greenway v. Ryan , 866 F.3d 1094, 1095 (9th Cir. 2017).
2.
Against this backdrop, we are convinced that the Arizona Supreme Court applied its causal nexus test with respect to Spreitz's evidence of longstanding alcohol and substance abuse in violation of Eddings .
We quote again the Arizona Supreme Court's discussion of Spreitz's history of alcohol and substance abuse:
The record demonstrates defendant's longtime substance abuse problems. We note, however, that defendant's general problems with substance abuse are not essential to our decision here. We therefore decline to conclude that defendant was impaired by alcohol consumption to an extent that it interfered with his "capacity to appreciate the wrongfulness of his conduct or to conform his conduct to the requirements of the law." A[riz]. R[ev]. S[tat]. [Ann.] § 13-703(G)(1) ; see also State v. Medrano , 185 Ariz. 192, 194, 914 P.2d 225, 227 (1996) (citing Stokley , 182 Ariz. at 520, 898 P.2d at 469 ).
....
The sentencing judge found that defendant's ability to appreciate the wrongfulness of his conduct was not impaired on the night of the murder to any significant extent by substance abuse, emotional disorders, situational stress, or by a combination of these. Our review of the record convinces us that the trial court's finding was proper.
Spreitz I , 945 P.2d at 1280-81. This discussion demonstrates that the Arizona Supreme Court primarily concluded that Spreitz failed to show statutory mitigation under Ariz. Rev. Stat. Ann. § 13-703(G)(1) based on his intoxication on the night of the murder. "When applied solely in the context of statutory mitigation under § 13-703(G)(1), the causal nexus test does not violate Eddings ." McKinney , 813 F.3d at 810.
The plain text of the Arizona Supreme Court's decision, however, also clearly demonstrates that the court did not solely *1276apply its causal nexus test to Spreitz's evidence of statutory mitigation. The court initially recognized Spreitz's "general problems with substance abuse"-evidence that should have been relevant as nonstatutory mitigation-but concluded those problems were "not essential to [its] decision" because they did not show Spreitz was "impaired on the night of the murder." Spreitz I , 945 P.2d at 1280-81. In other words, the court did not acknowledge the relevance of longtime substance abuse as nonstatutory mitigation in the absence of a causal relationship to the crime. Instead, the court held that because there was no causal relationship, Spreitz's long-term alcohol abuse was not of significance-i.e. "not essential"-to the court's overall determination of either statutory or nonstatutory mitigation.
The Supreme Court, however, has been clear that " 'full consideration of evidence that mitigates against the death penalty is essential if the sentencer is to give a reasoned moral response to the defendant's background, character, and crime.' " McKinney , 813 F.3d at 812 (first emphasis added) (quoting Penry I , 492 U.S. at 319, 328, 109 S.Ct. 2934 ). Accordingly, " Eddings requires that '[t]he sentencer must also be able to consider and give effect' " to any relevant mitigation evidence proffered by the defendant, which includes evidence going toward nonstatutory mitigation. Id. (quoting Penry I , 492 U.S. at 319, 328, 109 S.Ct. 2934 ). The Arizona Supreme Court's refusal to consider Spreitz's alcohol and substance abuse beyond its connection, if any, to Reid's murder constitutes application of its unconstitutional causal nexus test to relevant nonstatutory mitigation evidence.
Our understanding of the Arizona Supreme Court's opinion is bolstered by the fact that in its discussion of Spreitz's longstanding alcohol and substance abuse, the court cited to a prior decision that likewise applied the unconstitutional causal nexus test, State v. Medrano , 185 Ariz. 192, 914 P.2d 225 (1996). In McKinney , we explained that in Medrano , the Arizona Supreme Court upheld the sentencing judge's determination that the defendant's cocaine use failed as a nonstatutory mitigating circumstance because he did not show that it contributed to his conduct on the night of the murder. McKinney , 813 F.3d at 825-26. In so doing, "[t]he Arizona Supreme Court applied the causal nexus test." Id. at 825. Although the Arizona Supreme Court's citation to Medrano is not dispositive, it certainly corroborates our understanding of the court's opinion. See also Poyson , 879 F.3d at 890 (emphasizing, among other considerations, that the Arizona Supreme Court cited a passage from a case specifically identified in McKinney as applying the unconstitutional causal nexus test in order to conclude that the state court also applied that test to Poyson's evidence). Moreover, as we explained in McKinney , "the Arizona Supreme Court applied its unconstitutional nexus test consistently" for fifteen years because it had "a mistaken understanding of Eddings ." 813 F.3d at 826. It is thus entirely logical that in citing the exact portion of Medrano where it previously applied its causal nexus test, the Arizona Supreme Court was applying the same test in Spreitz's case. See id. at 821 ; see also Poyson , 879 F.3d at 890.
We find further support for our understanding of the Arizona Supreme Court's unconstitutional treatment of Spreitz's alcohol and substance abuse when we compare it with the manner in which the court discussed other mitigating factors. As detailed earlier, in evaluating the evidence of Spreitz's general history of alcohol and substance abuse, the court stated that this evidence was "not essential" to its decision. Spreitz I , 945 P.2d at 1280. By contrast, when the court considered other mitigating *1277factors, it specifically discussed the weight it would give those factors, as opposed to simply dismissing them outright. For example, when discussing Spreitz's subnormal upbringing, the court stated, "Although we recognize defendant's upbringing as a mitigating circumstance, we accord it little weight ." Id. at 1280 (emphasis added). As another example, after "finding that since his arrest, [Spreitz] has demonstrated remorse," the court stated that his "remorse for his actions does little to counterbalance especial cruelty as a serious aggravating circumstance." Id. at 1281 (emphasis added). And finally, when discussing the sentencing judge's determination regarding Spreitz's emotional immaturity, the court stated, "We also find that the sentencing judge ... properly found that his emotional immaturity was not a significant mitigating factor." Id. (emphasis added). In other words, when the Arizona Supreme Court wanted to assign weight to a given factor, it said so. This pattern stands in stark contrast to the court's conclusion that anything related to Spreitz's long-term alcohol or substance abuse that fell short of the statutory definition could not serve as mitigation. Id. at 1280-81.
Finally, as also discussed earlier, the PCR court distinctly interpreted the Arizona Supreme Court's decision as having applied a causal nexus test. The PCR court explained that "[w]ithout some basis for explaining or defining the individual's behavior at the time of the offense, [Spreitz]'s history of alcohol or substance abuse would be inconsequential (which is exactly what the trial court and Supreme Court concluded )." Moreover, in articulating how the Arizona Supreme Court had applied its causal nexus test in Spreitz's direct appeal, the PCR court, as had the Arizona Supreme Court, cited to a decision of the Arizona Supreme Court indisputably applying an unconstitutional nexus test, State v. Kayer , 194 Ariz. 423, 984 P.2d 31 (1999). See McKinney , 813 F.3d at 816 (explaining that Kayer held "that the defendant's mental impairment 'was not established as a nonstatutory mitigating factor' in part because 'defendant offered no evidence to show the requisite causal nexus that mental impairment affected his judgment or his actions at the time of the murder' " (quoting Kayer , 984 P.2d at 46 )). The fact that the PCR court interpreted the Arizona Supreme Court's opinion as we do-and then itself applied the constitutionally erroneous nexus test-lends further support to our reading.
We recognize that the Arizona Supreme Court's decision on the particular issue before us was framed by language that might, in a decisional vacuum, suggest the court knew, understood, and applied the law with respect to Eddings . The court acknowledged that Spreitz argued that his history of alcohol and drug abuse served as both a statutory and nonstatutory mitigating factor. Spreitz I , 945 P.2d at 1279. It then stated that it "must consider any aspect of the defendant's character or record ... relevant to determining whether the death penalty should be imposed." Id. And finally, in reaching the conclusion to affirm Spreitz's death sentence, the court explained that it had "examin[ed] the entire record and reweigh[ed] the applicable aggravating and mitigating factors." Id. at 1281-82.
The Arizona Supreme Court's acknowledgment of what Spreitz argued does not indicate that it relied on or accepted that argument as correct. Further, we cannot, given McKinney , Poyson , and Greenway , proceed in a decisional vacuum.
Considered in light of the baseline that the Arizona Supreme Court was consistently applying its unconstitutional causal nexus test in death penalty cases at the time Spreitz's appeal was decided, as well as its citations to cases held in McKinney *1278to be applying that standard, we are confident that the manner in which the Arizona Supreme Court disposed of Spreitz's evidence of his longstanding alcohol and substance abuse confirms that it applied the causal nexus test it was using during that period.
Styers v. Schriro , 547 F.3d 1026 (9th Cir. 2008) supports this conclusion. Styers stated that the mere fact that "the Arizona Supreme Court stated that it had 'considered all of the proffered mitigation,' " is not sufficient to contradict the fact that "its analysis prior to this statement indicated otherwise." Id. at 1035 (internal citation omitted). In Styers , notwithstanding assertions to the contrary, the Arizona Supreme Court refused to consider evidence of the defendant's Post Traumatic Stress Disorder ("PTSD") because he had failed to connect it causally to his crimes. Id. Here, too, the Arizona Supreme Court's actual analysis of Spreitz's longstanding alcohol and substance abuse reveals that it refused to consider this particular aspect of Spreitz's character free from any connection to the crime. Rather, the court's discussion demonstrates that in evaluating Spreitz's long-term alcohol and substance abuse, it applied a causal nexus test in violation of Eddings and therefore refused, as a matter of law, to consider it in assessing Spreitz's evidence of nonstatutory mitigating circumstances.
To the extent the state argues the Arizona Supreme Court's opinion is ambiguous as to whether it applied an unconstitutional causal nexus test or not-and we believe that it is not- McKinney requires resolving that ambiguity in favor of Spreitz. McKinney held it clear that the Arizona Supreme Court "consistently articulated and applied its causal nexus test" at the time the trial court imposed Spreitz's death sentence and the Arizona Supreme Court reviewed and affirmed that sentence. McKinney , 813 F.3d at 803 (emphasis in original). Again, "if there is to be a presumption, it is that the Arizona Supreme Court violated the dictates of Lockett and Eddings ." Greenway , 866 at 1095.
In sum, because (1) the Arizona Supreme Court clearly stated that Spreitz's longstanding alcohol and substance abuse was "not essential" to its decision, which was in line with the court's consistent practice of applying a causal nexus test; (2) the Arizona Supreme Court cited to Medrano , in which it had previously articulated a causal nexus test; (3) the Arizona Supreme Court carefully laid out the weight it would accord other mitigating factors as opposed to simply ignoring them; and (4) the PCR court likewise interpreted the Arizona Supreme Court's opinion as applying a causal nexus test, we conclude that the Arizona Supreme Court held, as a matter of law, that Spreitz's long-term alcohol and substance abuse was not a nonstatutory mitigating factor and therefore refused to consider it. This holding was in clear violation of Eddings .
3.
In light of our conclusion that the Arizona Supreme Court failed to comply with Eddings , we must next decide whether Spreitz was prejudiced by this error. On federal habeas review, relief is warranted if an error "had substantial and injurious effect or influence" on the challenged decision. See Brecht v. Abrahamson , 507 U.S. 619, 623, 113 S.Ct. 1710, 123 L.Ed.2d 353 (1993). The petitioner is "not entitled to habeas relief" unless he can establish that the error "resulted in actual prejudice." Davis v. Ayala , --- U.S. ----, 135 S.Ct. 2187, 2197, 192 L.Ed.2d 323 (2015) (internal quotation marks omitted). Here, because we are "in grave doubt about whether [the Arizona Supreme Court's] error of federal law had substantial and injurious effect or influence in *1279determining [whether to affirm Spreitz's death sentence], that error is not harmless. And, [Spreitz] must win." McKinney , 813 F.3d at 822 (quoting O'Neal v. McAninch , 513 U.S. 432, 435, 115 S.Ct. 992, 130 L.Ed.2d 947 (1995) ).
We previously have required resentencing based on prejudicial Eddings error where the Arizona Supreme Court refused to consider, as a matter of law, mitigation evidence "central to" the petitioner's "plea for leniency." See id. at 823 ; see also Coleman v. Calderon , 210 F.3d 1047, 1051 (9th Cir. 2000) (concluding that a penalty-phase jury instruction error was not harmless under Brecht because "it undermined the very core of Coleman's plea for life").14 For the reasons that follow, it is clear that Spreitz's long-term alcohol and substance abuse was important mitigation evidence, and was so closely related as to become central to his plea for leniency. The Arizona Supreme Court's refusal to consider that evidence had a substantial and injurious effect on its sentencing determination that requires resentencing.
While a defendant's evidence of longstanding alcohol and/or substance abuse can be probative mitigation evidence on its own, a "history of substance abuse [is] substantially mitigating when ... combined with other mitigating evidence." Henry v. Ryan , 720 F.3d 1073, 1090 (9th Cir. 2013) (emphasis added) (listing cases and holding that the defendant's alcoholism "would not have had a substantial and injurious effect" because it "st[ood] alone, was similar to evidence already considered by the sentencing courts, and was of limited probative value") (footnote omitted).15 Here, Spreitz's evidence regarding his history of alcohol and substance abuse-spanning nearly half his life by the time he committed the crime at the age twenty-two-was the factor on which much of his other mitigation evidence turned.
In both his report and his testimony, Dr. Flynn discussed at length the extent to which alcohol consumed Spreitz's life in the decade leading up to Reid's murder. Spreitz began drinking when he was twelve or thirteen; by fifteen, he was drinking steadily on the weekends and drinking vodka before school. According to Dr. Flynn, "[d]rug and alcohol abuse dominated his teenage years." After he left home, Spreitz's drinking intensified: Spreitz experienced blackouts multiple times and, a week before the murder, Spreitz was "intoxicated a majority of the *1280time." Dr. Flynn concluded that "[i]t appears completely clear from the available information that ... Spreitz had a long-standing problem with alcohol which probably reached the level of physical dependence."
Critically, Spreitz's decade-long struggle with alcohol and other addictive substances reflects the true gravity of his "subnormal upbringing," a mitigating circumstance recognized by the Arizona Supreme Court. See Spreitz I , 945 P.2d at 1280. Both Spreitz's sentencing memorandum and Dr. Flynn detailed how his difficult childhood led to Spreitz's early dependence on alcohol. For instance, Dr. Flynn explained that Spreitz turned to alcohol as a coping mechanism to deal with the "pervasive subabusive emotional battering and neglect that he received from his mother," whom he described as "punitive, controlling, [and] emotionally cold." Dr. Flynn found that Spreitz "slipped quietly into alcoholic numbness" after his "failure to live up to his mother's standards or earn her love." Reflecting parental neglect, Spreitz's parents "failed to arrange ... for an appropriate rehabilitation program" even though "[v]irtually everyone ... who spent much time with him described him as a heavy drinker." "Given the intensity and duration" of Spreitz's reliance on alcohol, "the mother (and step-father) were either so uninvolved with him to have failed to notice the problem, or they were aware of it and failed to arrange (or attempt to arrange) for an appropriate rehabilitation program."
Because Spreitz did not receive treatment during his teenage years, his dependence on alcohol only deepened. In his sentencing memorandum, Spreitz, too, argued that his long-term alcohol abuse reflects the impact that his upbringing by an emotionally unavailable, manipulative, punitive mother had on him: it was "[n]o wonder that by 12 or 13 [h]e began drinking alcohol and smoking marijuana." Although the Arizona Supreme Court recognized that Spreitz's "subnormal" upbringing was "a mitigating circumstance," it "accord[ed] it little weight." Spreitz I , 945 P.2d at 1280. Had the court properly considered Spreitz's longstanding history of alcohol abuse in conjunction with and as a manifestation of his disturbing childhood, both mitigating circumstances-and most importantly, the two in combination-would have been more compelling.
The dissent argues that Spreitz's long-term history of alcohol abuse cannot be central to his plea for leniency because much of his mitigation evidence focused on his "abusive and dysfunctional childhood, upbringing, and interactions with his mother," Dissent at 1293, not his history of alcohol and substance abuse. This argument, however, misses the point, as it overlooks the interlinked relationship between Spreitz's alcoholism and his subnormal childhood: Spreitz's history of alcohol and substance abuse is central to evaluating the actual significance of his childhood as a mitigating factor, and vice versa.
In addition to being a symptom of his dysfunctional childhood, Spreitz's alcohol and substance abuse can be seen as linked to his emotional immaturity, another nonstatutory mitigating circumstance recognized by the Arizona Supreme Court but described as not "significant." Spreitz I , 945 P.2d at 1282. In his report, Dr. Flynn explained that Spreitz was "very likely to have been socially and emotionally immature" due, at least in part, to "[y]ears of alcoholism intoxication [that] wipe[d] out many of the ... healthy developmental processes requisite to age-appropriate social and emotional maturity." Similarly, in his sentencing memorandum, Spreitz connected "[h]is developmental failure" with his "[n]umbing by use of alcohol." Again, had the Arizona Supreme Court properly *1281considered Spreitz's longstanding alcohol and substance abuse, another mitigating factor-Spreitz's emotional immaturity-would have been brought into proper perspective.
Thus, by failing to consider Spreitz's longstanding alcohol and substance abuse, the Arizona Supreme Court was left with a critical void in Spreitz's narrative: Spreitz's subnormal childhood was so emotionally disturbing that it led him to drink by the age of twelve or thirteen, which, in turn, disrupted his normal development and contributed to his emotional immaturity. As both a symptom and cause of other mitigating factors, Spreitz's longstanding alcohol abuse was thus central to his plea for leniency.16 Without consideration of the evidence of his long-term substance and alcohol abuse, the Arizona Supreme Court's conclusions regarding all of Spretiz's mitigation evidence were fundamentally flawed.
We come to this conclusion fully recognizing, as the dissent emphasizes, that "the severity of an aggravating circumstance must be considered when determining whether an Eddings error is harmless." Dissent at 1295. The Arizona Supreme Court described what Spreitz's "confession and physical evidence" revealed: that "Spreitz beat and raped [Reid] in a brutal assault that lasted many minutes before he crushed her skull." Spreitz I , 945 P.2d at 1279. For this reason, the Arizona Supreme Court affirmed the sentencing court's finding that Reid's murder was especially cruel. Id. Even so, we found prejudicial nexus-error in McKinney where the murder was done in a cruel manner for pecuniary gain as part of a double murder. McKinney , 813 F.3d at 823. "When the choice is between life and death," "the risk that the death penalty will be imposed in spite of facts which may call for a less severe penalty. ... is unacceptable." Abdul-Kabir v. Quarterman , 550 U.S. 233, 264, 127 S.Ct. 1654, 167 L.Ed.2d 585 (2007) (quoting Lockett v. Ohio , 438 U.S. 586, 605, 98 S.Ct. 2954, 57 L.Ed.2d 973 (1978) ). Accordingly, the sentencer "must be able to give meaningful consideration and effect to all mitigating evidence that might provide a basis for refusing to impose the death penalty on a particular individual, notwithstanding the severity of his crime ." Id. at 247, 127 S.Ct. 1654 (emphasis added).
Here, the Arizona Supreme Court failed to give any meaning to Spreitz's longstanding alcohol and substance abuse, an oversight which, in turn, minimized the value of other mitigating evidence as well. Because the court's analysis was missing a core component, we "cannot say, with fair assurance" that the Arizona Supreme Court's Eddings error did not affect its decision. McKinney , 813 F.3d at 822. As a result, the Arizona Supreme Court's refusal to consider the evidence was not harmless under Brecht .
IV. Conclusion
We reverse in part the district court's judgment denying a writ of habeas corpus. We remand with instructions to grant the writ with respect to Spreitz's sentence unless the state, within a reasonable period, either corrects the constitutional error in his death sentence or vacates the sentence and imposes a lesser sentence consistent with the law.
*1282REVERSED in part and REMANDED.